mark kibort

Who has experiemented with lap time comparisons with and without using the GT3 Cup car ABS?

Different than other ABS systems on other cars you have raced?

jrgordonsenior

Unfortunately they're 2 different cars. The 6-cup with ABS, and the later 7-cups without. The later 7-cups have more HP and a superior suspension design. I can say that almost all drivers I know who have switched are faster in the 7-cup though many have struggled with the non ABS brakes....

Geoffrey

The 997 brake system also has almost no pedal feel and a very, very hard pedal due to too large master cylinders. Further, if you are trailbraking heavily into a bumpy brake zone and the brakes are locking when the wheel is off the ground, the transmission will not downshift for you. So, your braking is tied into shifting with some compromizes having to be made.

mark kibort

Did I understand you correctly? There is no ABS in the 997GT3cup?
someone else mentioned that the 996s could be faster in the turns and under braking vs the 997 cups. Is this due to ABS or weight or class weight, or something else, or not true.

Just curious.

By the way, pretty interesting to see the cup car in WCGT at long beach hang in there with the motorsport upgraded speedGT GT3s, all on DOTs. I think Stanton was only about 1-2 seconds off the pace.

mk

Geoffrey

The 996 GT3 Cup is not faster in the corner as it does not benefit from the improved suspension geometry of the 997 Cup. You understand correctly, the 997 Cup has a dual AP Racing master cylinder setup with adjustable bias and NO ABS.

Fishey

Why do people not back date the ABS system if there is a possible gain? or have they done it.

jrgordonsenior

Update/backdate is only legal within the same model type. The 6-cup is GTC3 and the 7-cup GTC4. Different model types....

Fishey

Seems like a dumb move my Porsche not to include it then.

allegretto

I'm not sure the 6-Cup ABS will even work on a 7-Cup

BGB Motorsports

I could be wrong but I don't think there's boost assist on the 997 Cup car. The pedal lacks feel and is hard for some to get acclimated to. Furthermore, among the 996 Cup cars, there's no ability to execute a back-to-back comparison, as it's nearly impossible to race a 996 Cup Porsche or street based 997 Porsche with DISMANTLED ABS on track due to the large abundance of front brake bias. It's merely an exercise in front tire purchasing.

When the cars first came out, the brakes in the 997 were fickle and took some getting used to. The feedback was thus that at Daytona in the rain, the 996 was an easier car to drive at the 24 in 2006 and 2007 and therefore, the 996 was deemed to have an advantage under braking in unfavorable conditions. Tricks and development have cleared up some of the issues that make them hard to handle.

supercup

996 Cup ABS can be retrofitted to a 97 Cup. We have a 2006 997 Cup in our shop that has been done, works great, but you lose the ability to adjust the bias. So there are trade offs.

JCM

allegretto

thanks for the heads-up! maybe i'll look into to that this season.

one thing; if one has ABS, what's the point of bias? i mean, i understand both and up to threshold bias makes sense of course, but let's be honest, it's tougher than hell to delicately balance the brick that is the brake pedal of a 7-Cup!

coryf

If the bias isn't correct one axle will engage ABS too soon relative to the other. Threshold braking is much more efficient than the cycling ABS braking so if one axle is engaged in ABS it will not be stopping as well as it could.

Changing to a smaller master sizes will greatly improve the pedal feel as well.

I also should be possible to add ABS while still retaining the 997 masters and keep the adjustable bias. Just plumb the lines from the ABS block to the stock 997 master's.